Skin coloring compositions



Jase.

United States Patent SKIN COLORING COMPOSITIONS Nicholas BernardSiccama, 659 Squaw Brook Road, N.H., Paterson 3, N.J., and William L.Wirbelauer, deceased, late of Wyckolf, N.J., by Donald J. Chapman andHarry E. Hasselmann, executors, both of 70 Pine St., New York 5, N.Y.

No Drawing. Filed Oct. 9, 1957, Ser. No. 689,044

Claims. (Cl. 167-90) This invention is a continuation-impart of copending application Serial No. 534,388, filed September 14, 1955, nowabandoned, in turn a continuation-impart of application Serial No.459,851, filed October 1, 1954, the latter of which is now abandoned,which relate to several compositions for coloring human skin, and othersurfaces of the human body, such :as the hair [and nails, etc., thisapplication being directed to compositions for coloring the human skinto any desired color or tint adapted as a composition in lotion, cream,gel or paste formfor application as a cosmetic to form a coloredprotective skin tanning and sun screening coating upon the skin. Moreparticularly, the dermal coloring composition comprises a water solublecolorless indigoid ester dissolved in an aqueous carrier, criticallyadjusted in pH to a slightly alkaline range above 7 /2, preferably notexceeding about 8 /2, the solution being preferably combined with skinpenetration, levelling and fixing substances, enhancing the penetrationof the composition into the outer layer of the skin and hair.

The composition of this invention imparts an evenly diffused and firmlyfixed color developed in situ on the skin by precipitation of acolorless soluble indigoid ester as a colored insoluble pigment, uponexposure to light. The composition prior to use has relatively permanentchemical stability in storage in containers and, upon application to theskin as a cosmetic product, is activated to a colored coating by lightexposure.

It is accordingly the primary object of this invention to provide skincoloring compositions comprising substantially colorless vat esters,preferably indigoid esters, soluble and stable in aqueous or aqueousalcoholic solutions which are alkaline, the composition furtheressentially containing a fixative and, desirably, skin penetrative,dispersing or wetting and levelling agents whereby the colorless estermay evenly penetrate into the top epidermis layer of the skin, thecomposition being adapted to develop and become fixed on the skin in adesired pigment form, firmly adherent to the skin, upon exposure tolight for a short period of time. The composition for converting todesired viscous liquid, gel or paste form may further contain athickening agent to optimum cosmetic choice consistency and to allowcareful application to specific areas to be tinted.

In addition to the superior properties of a substantially THE SKINCOLORING COMPONENT The substantially colorless esters which are usefulin the present invention are a specific group within the broad class ofreduced vat colors. The broad class of vat dyes in their so-calledsoluble colorless form are characterized by being water soluble and someare colorless, or substantially so but most are not, and they are allcommonly precipitated to colored insoluble pigment form in normal usefor dyeing of textiles at high temperatures including treatment withacids, oxidizing mediae and hot soap solutions, treatments which couldnot be applied to the human skin because of their harmful reaction asstrong, heavy chemicals.

The practically colorless ester compounds useful herein are alkalimetal, typically sodium, sulfate ester derivatives of 1-4 conjugated diketo radicals preferably contained in an indigoid system. Our estercompounds contain in their ring system the grouping Such grouping is areduced or enol form of the colored insoluble keto grouping colorlessor, if preferred, desirably slightly colored comformed by hydrolysis ofthe ester and rearrangement by oxidation.

The soluble colorless esters of the indigoid ring system, which are apreferred type, have the structure wherein X is sulfur or imino and ARcompletes a single or multiple aromatic ring system containing suchradicals as benzene and naphthalene, and which may be substituted withlower alkyl, lower alkoxyl, thio alkyl and halogen groups such aschlorine or bromine. While the single sodium sulfate ester is shown onone hydroxyl, both hydroxyls may be esterified with sodium sulfate estergroups.

When the colorless indigoid compound is exposed to light after coatingupon the skin and in the presence of a fixative, the ester grouphydrolyzes off, the compound rearranges to the keto form, and the colordeveloped keto compound has the following structure:

4; X \H/ ll AR AR where X and AR are the same as defined above.

The soluble vat esters are well known in the dyeing art for textiles andare commercially available under the names Algosols, Indigosols, Calcosoluble vats, S'olvats, Dupont, Soluble Vats, Anthrasols, and others. I

The following are a few esters selected to illustrate a range of colorsthat develop when the ester is converted to pigment (keto) form:

Algosol (or Indigosol) Brown IRRD (PR-421) sodium sulfate ester ofbis-2-1-naphthophen indigo Algosol Orange HR (CI-1217) sodium sulfateester of ethoxy thio indigo CrHrO Algosol Red IRH (CI-1212) sodiumsulfate ester of his (-ch1oro-7-methyl) thio indigo Algosol Red VioletIRRN (PR503) sodium sulfate ester of bis(4,7-dimethyl,5-chloro) thloindigo on, on; Cl-

Cl S 0 CH; CH5

Algosol Blue 04B (CI-1184) sodium sulfate ester of his5,7-dibromo-indigo I? H Br 0 it I 0 0:0 Br i (l Many other soluble estercompounds may be selected from the similar known compounds of the artand mixtures of compounds may be used for variation of tint and shade toobtain the color desired.

Moreover, the color may be selected to effect a shade corresponding tosome unusual purpose. For instance, a standard light brown color mightbe applied to the legs to simulate the conventional color of sheerstockings to make their absence less noticeable if none are worn.

Color forming compositions may also be selected, if desired, to give alighter pigment effect to skin that is naturally dark.

pH RANGE It will be understood that the esterifying sodium sulfate groupmaintains the structure of the color forming compound in its colorlessand reduced state and renders the compound water soluble. Thesecompounds must be maintained substantially alkaline at a pH above 7.5and preferably in the range of 7.5 to about 8.5 because they willhydroyze to colored form in storage in containers at a lower pH.

The essential alkaline condition of the composition is stressed, becauseany substantial lowering of pH tends to produce some trace hydrolysis ofthe ester. For instance, at a pH below about 7.2, trace quantities ofthe ester become hydrolyzed and progressively oxidized with consequentproduction of hydrolytic products in solution including sulfuric acidions. These tend to accelerate the hydrolysis so that thereafter, in arelatively short storage period, the colorless ester compound becomescompletely hydrolyzed and precipitated from solution to coloredinsoluble form in storage, rendering the total composition useless forpresent purposes.

Where the pH of the solution substantially exceeds 8.5 the rate ofdevelopment of color is substantially retarded beyond a reasonably shortperiod of light exposure such as more than thirty minutes. Accordinglyat a pH below 7.5 the composition is unstable in storage and gives anuneven and poorly adherent coating; and at pHs above 8.5 the time ofexposure necessary to develop color may be inconveniently extended.

The pH adjustment is essential and is preferably done on the leuco esterdye substance per se, usually adding small quantities of soda ash orother alkaline substance to the leuco ester dye sufiicient to producethe desired pH in solution. It may be again adjusted in the finalcomposition to assure the required stability, available in the alkalinestate.

The soluble indigoid ester in its adjusted alkaline state is dissolvedin water or in an aqueous water miscible solvent such as a loweralcohol. The final composition for desirable coloring effect shouldcontain from about 0.1 to 5% by weight of the ester homogeneouslydissolved therein. Usually more pronounced color tinting eifects aredesired than is available in quantities near the lower limit, so that apreferred range of ester is from 0.5 to 3% or more. The most usuallydesired color effects upon the skin are available in quantities of about1.5%. However, that color eifect may be obtained by several applicationsof more dilute color forming compositions. Sometimes for highly coloredlocalized areas in a single application such as for coloring the hands,it is desired to use much higher color concentrations and 3 to 5%,usually about 4%, will be used.

In formulating the composition, the colorless ester may be made upinitially in a substantially more highly concentrated solution inalcohol or water as a stock solution for blending with other desirablecomponents such as diluent carriers, skin penetrative substances,levelling agents, etc. which may be present in substantial quantities.Hence, an initial solution of the ester in water or a mixture of waterand alcohol may be made in concentration substantially exceeding thisrange but which will be ultimately diluted by other components added tothe composition so that the ester concentration in the final compositionas used for coloring will be in the ranges given.

LIGHT EXPOSURE The alkaline aqueous or aqueous alcohol color formingester solution when combined with a fixative and applied to the skinwill develop color on exposure to light. The time period for colordevelopment in combination with the fixative is relatively short rangingfrom a few minutes up to about thirty minutes, more or less, variablewith the amass? type of light. Any type of light over a broad wavelength band from about 2900 to 8000 a.u., a range encompassing bothvisible and ultra violet light, and referred to as actinic light, willdevelop color by the color forming ester on the skin in the preferred pHadjustment of 7.5 to 8.5. The period of color development will begreatly accelerated and the time period thereby reduced to a few minuteswhen the exposed coated body portion is exposed to light of shortwavelengths such as the ultra violet range of about 2900 to 3600 an. asavailable from a suntan lamp radiating light in that range. In ordinaryvisible light range the time of color development is longer such as upto about thirty minutes after application to the skin. In brightsunlight color development is readily obtained in shorter periods suchas even less than five minutes of exposure depending on the lightintensity.

The pigment deposits in and on top of the outer skin layer by that lightexposure and forms a continuous screening film having the property ofabsorbing light, as usual with pigments, and has inherently asubstantial protective effect upon the skin to absorb and filter light,thereby increasing the resistance of the skin to sunburn.

FIXING AGENTS We have further found that it is essential that thecomposition contain a substance adapted to accelerate color developmentand to fix or mordant the ultimately precipitated color upon the skin ina firmly adherent manner as a colored coating of substantial permanence.Particularly, it is found that indigoid ester solutions applied to theskin, while they will develop some color after long periods such asseveral hours of light exposure, as explained above, are readilyremovable, since the skin naturally contains oily substance which moreor less tends to prevent adhesion and skinpenetration, an effect whichmay be somewhat offset by inclusion of skin penetrative substances inthe composition. It is found, however, that a fixing agent tends to actas a coupling agent to secure fixation of the color upon the skin. Thatfixing agent has the equally important property of reducing the timeperiod of color development under light exposure.

More particularly, we have found that a specific group of fixing agentsare outstandingly useful, not only to effect a relatively permanentbonding of the color upon the skin, but which will greatly acceleratethe development of color after application and under light exposure.Useful fixing agents herein are water or alcohol soluble urea compoundsor amino acids and salts thereof having respectively the generalformulae:

ll RNHC-NHR ll 1 t"ooMe NH,

wherein X is a sulfur, oxygen or imino radical and R is hydrogen, loweralkyl, or hydroxy lower alkyl, R is lower alkyl of l-3 carbon atoms andMe is hydrogen, alkali metal, such as sodium or potasisum, and ammonium.The compounds generally are simple ureas such as urea, thio urea,guanidine; lower dialkyl ureas such as dimethyl urea, and dimethyl thiourea; and lower dialkylol ureas, such as dimethylol urea, dimethylolthio urea, diethylol urea and other ureas of similar characteristics,and simple amino acids or salts like glycine or alanine. The ureas oramino acids may all be homogeneously dissolved in the same solution ofcolorless ester and stably stored under alkaline conditions as explainedabove.

In compounding the fixative urea or amino acid compound dissolved withthe colorless ester in the same solution, the quantity used is about 2to 12% preferably about 4 to 8% by weight of the final composition.

6 SKIN 'PENETRATIVE, WETTING AND 'LfivELLINd COMPONENTS The human skinnormally carries a more or less oily coating which tends to resistwetting and penetration desirable for even coating of the skin. It ispreferred to modifiy the composition with penetrative substances whichallow even wetting and dispersing of the composition upon the skinsurface so that the composition for coloring purposes will be evenlyprecipitated as infinitesimal finely diffused insoluble deposits on tothe layer of the epidermis, that is, upon the outer skin surface. Toenhance the absorption by the skin, it is preferred to use substanceswhich are of a hydrophyllic character. That type of penetrativesubstance allows even coating and color development by the skin and,after even penetration, absorption and fixation of the color, allowsready removal of the carrier by washing, without, at the same time,removing the color which has become relatively permanently fixed uponthe skin. For instance, while carriers of other types might be used, andhave some benefit because of the emollient character, they are not onlydifficult to remove by washing, but most important for the purposes ofthe present composition, such oily, lipophyllic, substances tend todissolve the coloring components and prevent intimate wetting of theskin surface by the color forming ester necessary for permanentadhesion. Hence, upon washing of oily compositions on the skin, asubstantial amount of the coloring substance becomes removed.

Our preferred hydrophyllic skin penetrative substances comprise higheralcohols, usually liquid non-fatty 2-4 carbon atom alcohols, which mayhave 2-3 hydroxyl groups, all but one of which may be etherified oresterified. These higher alcohols are compounds having substantial wateror aqueous lower alcohol solubility. Useful skin penetrative substancesare polyhydroxy alcohols and partial esters thereof in which at leastone free hydroxyl group is retained, such as glycerine, ethylene glycol,propylene glycol; polyhydroxy alcohol ethers such as diethylene glycol,glycol mono lower (l-4 C atoms) alkyl ethers, such as mono ethyl etherof ethylene glycol, diethylene glycol mono lower alkyl ether such asmethyl, ethyl, propyl and butyl ethers of diethylene glycol commerciallyavailable as Carbitols; hydroxy lower aliphatic esters such asdiethylene glycol mono acetate, hydroxyethyl acetate and butyl lactate.The quantity of skin penetrative substance used is not critical, and itmay be omitted from the composition. We prefer to include the skinpenetrative substances for the reasons stated and it will normally beused in quantity of from 0.5 to 25 Weight perecent of the finalcomposition.

The composition further desirably includes levelling agents and wettingagents. The wetting agents tend to maintain the solutions clear, andenhance the penetration and ready removal of other carrier componentsafter color development. Typically useful wetting agents are the dioctylsodium sulfosuccinate commercially available as aerosols. Variouslevelling agents are useful and the aerosols inherently have somelevelling effect. We prefer to use a liquid aqueous alcohol solublesilicone polymer also known in the art as organopolysiloxane, forexample DC-555, a low viscosity non-toxic liquid polyphenyl silicone,for levelling and securing most smooth and even distribution of thecolor forming composition on the skin.

The levelling and wetting agents when used will be in small quantity ofabout 0.1 to 3 weight percent of the final composition. Such levellingagent and wetting agents give an improved final smooth even coating andwill usually be used in conjunction with the penetrative substancedefined above in the composition, but the wetting and levelling. as wellas the skin penetrative substances may be omitted with less desirableresults in perfect evenness of the color developed and in the otherdesirable properties mentioned. Some of the unevenness resulting fromomission of one or more of these components may be considerably reducedby repeated applications of a color forming composition to the skinwhereby several coats applied give a stronger as well as more evencolor. Oftentimes the practice of producing the color by an applicationconsisting of rubbing in several coats, allowing each to have its colordeveloped before applying the next, is a preferred practice, consideringthat repeated coatings tend to give a deeper and more intense color. Forinstance, it may be preferred to apply several color developingcompositions in a sequence, each of low pigment forming content, therebyto ultimately produce by repeated application of 2 or more the exactintensity and depth of color desired.

As indicated the composition may also be thickened to any desiredconsistency and conventional organic or inorganic filler or thickeningagents such as methyl cellulose, starch, polyvinyl alcohol, polyvinylpyn'olidone, gum tragacanth, carboxy methyl cellulose, algin, which mayalso have been of the character of inert filler substances, such asclay, bentonite, magnesium aluminum silicate, and the like, may beapplied in quantity to obtain the desired thickening. However, suchthickening agents have little if any effect on the penetration andlevelling of the color-forming solution into the skin. Particularly suchthickening agents are desirably used only to effect a thickening forimproved lotion or cream consistency and for more accurate fiow controluseful for localized application.

The composition may also contain such additives as are conventionallyuseful for specialized purposes for which the composition may be used.For example, in general skin coloring or in an after shave lotion thecomposition may further contain medicaments, per-fuming agents, etc.,and the composition may even contain trace quantities of ordinary colorsof any approved type to render the product saleably attractive, suchcolored additives being in quantity insuflicient to have any pigmentingor substantial ultra violet light retarding effect upon the skin. Suchadditives may conventionally consist of perfumes, menthol,G1l(2,2-dihydroxy,3',5,6,3,5,6 hexachlor diphenylmethane) all added intrace quantities for their known specific effects.

A suitable base formula for the composition is as follows:

Substance: Weight percent Colorless ester 0.1 to Fixative 2 to 12 Waterand optional additive Remainder to 100 Alkali to pH 7.5 to 8.5. Optionaladditives:

Skin penetrant 0.5 to 25 Ethanol or propanol 0. to 90 Levelling agent0.1 to 3 Wetting agent 0.1 to 0.3 Perfume, antiseptic, thickener, etcQ.S.

In formulating the composition the fixative urea is first dissolved inwarm, aqueous ethyl or propyl alcohol, or water if the solvent is to beentirely aqueous, and thereafter the colorless dry ester or mixture ofesters of proper alkalinity is added to the alcohol or water solution ofthe fixative. The solution may be warmed for rapid dissolving as high as70 C. and is thereafter allowed to cool. The pH thereof carefullyrechecked for adjustment with alkali or ammonia to the required range.Thereafter, the various additives when such are used are added in anysequence, preferably adding the skin penetrant substances, levellingagents, wetting agents, perfumes, antiseptics, etc. in that order withcontinuous stirring for homogeneous solution.

For application to coloration of the skin to produce for example a. tancolor. effect, the composition thus prepared O (a is rubbed over thearea of the skin for which color is to be imparted. This is preferablydone by use of an absorbent applicator such as a sponge, rubbing thecomposition evenly over the entire skin area to be colored as a singlecoating. That skin area is then exposed to light for the period of timesufficient to develop the color, depending upon the character of thelight as mentioned above. If desired that skin area may again be coatedwith several superimposed coatings, the same procedure being repeateduntil the color of desired depth and evenness is obtained.

The final color produced will not wash OE With ordinary substantiallyneutral light soapy solution, nor with hot, cold or salt water or evenusual detergents, cleansing liquids or solvents. However, a substantialportion of the color can be removed by a much stronger abrasive orscouring action applied with a substantially alkaline soap and warmwater.

The following are examples of useful compositions in severalapplications:

SKIN COLORING EXAMPLE I Component: Weight percent Leuco Ester Brown IRRD1.00 Leuco Ester Blue 0 13 .20 Silicone 555 (Dow) 3.00 Urea 6.00

Carbitol 0.50 Glycerine 0.50 Aerosol OT 0.20 Water 1000 Alcohol 78.60Ammonia pH 8.

EXAMPLE II IRRD 1.00 Carbitol 2.00 Glycerine 4.00 Thiourea 6.00, Ethylalcohol 57.00 Water 20.00 Polyvinyl alcohol thickener 10.00 Ammonia pH8.

EXAMPLE III IRRD 1.00

Carbitol 1.00 Glycerine 1.00 Dimethyl urea 10.00 Butyl lactate 2.00Water 10.00

Alcohol 75.00 Ammonia pH 8.

EXAMPLE Iv IRRD 1.00 Silicone 555 (D-C) 1.00 Guanidine 6.00 Aerosol OT0.50

Water 10.00 Aluminum magnesium silicate thickener 10.00 Alcohol 71.50Ammonia pH 8.

AFTER SHAVING LOTION EXAMPLE V Component: Weight percent Leuco EsterBrown IRRD 0.80 Leuco Ester Blue 0 B 0.16 Silicone 555 0.50

Glycine 4.00 Glycerine 0.50 Water 10.00

Alcohol 83.04

Perfume, etc. 1.00

Ammonia pH 8.

9 EXAMPLE VI IRRD 0.50 Silicone S55 (D-C) 0.50 Urea 3.00 Glycerine 1.00Water 5.00 Bentonite thickener 10.00 Alcohol 80.00 Ammonia pH 8.

EXAMPLE VII IRRD 0.67 Dirnethylol urea 4.00 Glycerine 1.00 Water 45.00Menthol Perfume} Alcohol 48.33 Ammonia pH 8.

We claim:

1. A skin coloring lotion comprising an aqueous solution of asubstantially colorless leuco indigoid ester compound developing colorupon exposure to actinic light and a water soluble fixative compoundselected from the group consisting of urea, thio-urea, guanidine, alower alkyl derivative of said urea fixative compound, a hydroxy loweralkyl derivative of said urea fixative compound, a lower amino acid, anda soluble salt of a lower amino acid, said composition having a pH inthe range of about 7.5 to 8.5.

2. A skin coloring lotion comprising an aqueous solution of asubstantially colorless leuco indigoid ester compound developing colorupon exposure to actinic light and small quantities of a water solublefixative compound selected 'fIOl'Il the group consisting of urea,thio-urea, guanidine, a lower alkyl derivative of said urea fixativecompound, a hydroxy lower alkyl derivative of said urea fixativecompound, a lower amino acid, and a soluble salt of a lower amino acidand an organopolysiloxane leveling agent and a thickener homogeneouslydistributed in said solution, said solution having a pH range of about7.5 to 8.5.

3. A skin coloring lotion comprising an aqueous solution of asubstantially colorless leuco indigoid ester compound developing colorupon exposure to actinic light comprising an aqueous solution of acolorless indigoid ester, a water soluble fixative compound selectedfrom the group consisting of urea, thio-urea, guanidine, a lower alkylderivative of said urea fixative compound, a hydroxy lower alkylderivative of said urea fixative compound, a lower amino acid, and asoluble salt of a lower amino acid, and a hydrophyllic skin penetrativesubstance, said solution having a pH in the range of about 7.5 to 8.5

4. A skin coloring lotion comprising an aqueous solution of asubstantially colorless leuco indigoid ester compound developing colorupon exposure to actinic light and small quantities of a water solublefixative compound selected from the group consisting of urea, thiourea,guanidine, a lower alkyl derivative of said urea fixative compound, ahydroxy lower alkyl derivative of said urea fixative compound, a loweramino acid, and a soluble salt of a lower amino acid, a leveling agent,a thickener and a wetting agent, said solution having a pH. range ofabout 7.5 to 8.5.

5. A skin coloring lotion comprising 0.1-5% of a substantially colorlesswater soluble leuco indigoid ester, about 2 to 10% of a water solubleurea fixative selected from the group consisting of urea, thiourea,guanidine, lower alkyl derivatives of said urea fixative compounds,hydroxy lower alkyl derivatives of said urea fixative compounds, andlower amino acids about 0.5 to 25% of a hydrophyllic skin penetrativesubstance selected from the group consisting of polyhydroxy alcoholshaving 2 to 4 carbon atoms and 2 to 3 hydroxyl groups, lower carboxylicacid esters of said polyhydroxy alcohols having at least one freehydroxyl group, lower alkyl ethers of said polyhydroxy alcohols havingat least one free hydroxyl group, hydroxy lower alkylene ethers of saidpolyhydroxy alcohols, and a lower alkyl ester of lactic acid, and theremainder to comprising water, all proportions being by weight, saidcomposition having a pH of from about 7.5 to 8.5.

6. A skin coloring lotion as defined in claim 5 wherein the compositioncontains up to 3% of organopolysiloxane and suflicient thickener tosubstantially raise the viscosity of the composition.

7. A skin coloring lotion as defined in claim 1 wherein the aqueouscarrier solvent is a dilute aqueous lower 23 carbon mono hydric alcoholsolution.

8. A skin coloring lotion as defined in claim 5 wherein the aqueouscarrier solvent is a dilute aqueous lower 2-3 carbon mono hydric alcoholsolution.

9. A skin coloring lotion comprising an aqueous a1- coholic solution ofa substantially colorless leuco indigoid ester compound developing colorupon exposure to actinic light, and a soluble amino acid fixativesubstance to accelerate color development upon light exposure and toafiix the developed color upon the skin surface, said solution having apH range of about 7.5 to 8.5.

10. A skin coloring lotion comprising an aqueous solution of asubstantially colorless leuco indigoid ester compound developing colorupon exposure to actinic light and a water soluble fixative compoundselected from the group consisting of urea, thio-urea, guanidine, alower alkyl derivative of said urea fixative compound, a hydroxy loweralkyl derivative of said urea fixative compound, a lower amino acid, andan organopolysiloxane leveling agent for said colorless indigoid ester,said lotion being thickened with magnesium aluminum silicate andadjusted to a pH range of about 7.5 to 8.5.

References Cited in the file of this patent UNITED STATES PATENTS1,918,158 Weisberg July 11, 1933 2,695,259 Carle Nov. 23, 1954 FOREIGNPATENTS 671,122 Great Britain Apr. 30, 1952 949,467 France Feb. 21, 1949OTHER REFERENCES Vat Dyes, The Application of, A.A.T.C.C. Monograph No.2, Am. Asso. of Textile Chemists and Colorists, 1953, pp. 94, 95,256-301.

Plein: J. Amer. Pharm. Asso., Sci. ed., 42:2, February 1953, pp. 79-85.

McGregor: Silicones and Their Uses, McGraw-Hill Book Co., N.Y., 1954,pp. 42 and 89.

Chemical Week, July 17, 1954, p. 52.

1. A SKIN COLORING LOTION COMPRISING AN AQUEOUS SLUTION OF ASUBSTANTIALLY COLORLESS LEUCO INDIGOID ESTER CONPOUND DEVELOPING COLORUPON EXPOSURE TO ACTINIC LIGHT AND A WATER SOLUBLE FIXATIVE COMPOUNDSELECTED FROM THE GROUP CONSISTING OF UREA, THIO-UREA, GUANIDINE, ALOWER ALKYL DERIVATIVE OF SAID UREA FIXATIVE COMPOUND SELECTED FROMLOWER ALKYL DERIVATIVE OF SAID UREA FIXATURE COMPOUND, A LOWER AMINOACID, AND A SOLUBLE SALT OF A LOWER AMINO ACID, SAID COMPOSITION HAVINGA PH IN THE RANGE OF ABOUT 7.5 TO 8.5.